Category Archives: Radio history

1942 Two-Tube Broadcast/Shortwave Receiver

1942SepPM1The father-daughter team shown here are putting the finishing touches on the plug-in coils for the two-tube broadcast/shortwave receiver described in the September, 1942, issue of Popular Mechanics.  The set was designed to build upon a one-tube receiver described in the magazine’s July issue.

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Most of the parts, as well as the chassis, of the earlier set were re-used to make the more complex receiver shown here. The 1Q5GT detector was re-used, and another 1Q5GT was used as audio amplifier. On strong local broadcast stations, the set would provide loudspeaker volume. For weak distant shortwave stations, the set would provide excellent headphone volume. The five homemade plug-in coils would provide the regenerative receiver with coverage from the broadcast band through 20 meters.

Three power supplies were required. A 1.5 volt dry cell was used for the filament voltage, and four flashlight batteries were used for the bias voltage. The B+ was supplied either by a 45 volt battery or a battery eliminator which was also shown.

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Buzzer Converted to Telegraph Sounder

1917SeptPMThis illustration appeared in Popular Mechanics a hundred years ago this month, September 1917, and illustrates a clever solution to a problem that no longer exists.  It shows a simple way to convert a buzzer into a telegraph sounder.

At first blush, it seems rather obvious how to use a buzzer as a telegraph:  Simply hook it up, as shown, in series with the key and the battery.  If that’s how it were hooked up, that’s how I, or just about anyone who knows Morse Code these days, would be able to listen with ease.

It took me a few minutes to realize what was going on.  This was a simple way to create a sounder that would sound like a landline telegraph.  That kind of telegraph didn’t produce a continuous tone, as Morse Code does when sent by radio.  Instead, it produces clicks and clacks as the arm of the sounder hits the coil.  The landline telegrapher is listening for those clicks and clacks, the same way that I would be listening to the buzz of the buzzer.  But the buzzing would be just as incomprehensible to the landline telegrapher, just as the clicks and clacks would be incomprehensible to me.  The code being used is very similar (but not quite identical, since American telegraphers used American Morse, while radio operators use International Morse Code).  But the medium being used is very different.

The secret of the diagram above is the wire run from point C to point F.  Normally, a buzzer makes noise because the coil energizes and pulls the arm down.  But in the process, it breaks the electrical contact between the arm and point C.  This causes the coil to de-energize, and the arm swings back.  When it gets back in position, the coil is powered up again, and the cycle repeats.  This happens fast enough that a buzzing sound is produced.

In this diagram, the vibrator contact is shorted out.  So when the arm is pulled toward the coil, it stays there until the key is released, just as would happen in a landline telegraph sounder.  So instead of buzzing, the buzzer now clicks and clacks, and the aspiring landline telegrapher can use the modified buzzer to practice the trade.

According to the magazine, the idea was sent in by one Clarence F. Kramer of Lebanon, Indiana.  Interestingly, Mr. Kramer apparently knew both versions of the code, since he was also a radio amateur. He is listed in the 1921-23 call books as being licensed as 9AOB, with an address of 414 E. Pearl St., Lebanon, Indiana.  The April 1923 issue of Wireless Age shows that he pulled in, on a crystal set, 27 different broadcast stations, his best DX being 825 miles, WBAP in Ft. Worth, Texas.  Another one of the stations he pulled in was WLAG in Minneapolis, the forerunner of WCCO.  In the December 30, 1925 issue of the Indianapolis Star, he describes himself as an “ardent radio bug.”

He also appears to have been a Boy Scout, since one Clarence Kramer of Indiana, with various interests including wireless and telegraphy had a penpal request in the January 1915 issue of Boys’ Life magazine.  While it could be another person with the same name, one Clarence F. Kramer was an engineer with Ford, holding a number of patents.  If he went to work for Ford, then he is probably the Clarence Frank Kramer who died in Michigan in 1994 at the age of 92.



1957 Self-Powered Radio

1957SeptRadioElectronicsThe little circuit shown here appeared sixty years ago this month in the September 1957 issue of Radio Electronics magazine. Almost anyone who has experimented with electronics has probably tried a variation of this circuit. It’s simply a way to run a small electronic device from the “free” energy of a nearby broadcast station. The signal is picked up by the antenna, is rectified by a diode, and the resulting energy is used to provide power to a transistor audio amplifier.

The example shown here appears to use a single diode to both provide power to the transistor, and the signal. According to the magazine, the diagram comes from U.S. Patent 2777057, issued to one  Jacques J. Pankove, and assigned to RCA.  While the patent contains drawings for circuits that are slightly more complex, the diagram here does not appear in the patent itself.



Capt. Hawthorne C. Gray, 1889-1927

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Shown here in the September 1927 issue of Popular Radio is Capt. Hawthorne C. Gray of the U.S. Army Air Service, preparing for the flight in which he achieved the record for the highest altitude from which radio broadcast reception had ever been made.  According to the magazine, Capt. Gray’s balloon was equipped with an Atwater Kent Model 32, a seven-tube receiver with single dial control and loop antenna.  During the flight, he was able to pull in stations KMOX and KSD, and he was able to determine bearings to the stations at all times during the flight.  “Up to the time that the aviator became unconscious at 31,000 feet, the receiver was working satisfactorily, with a total lack of interference.”

The date of the flight is not stated in the magazine, but it appears to be the same flight that Capt. Gray recounted in the August 1927 issue of Popular Mechanics.

In that account, Capt. Gray notes that he was listening to a jazz orchestra playing in St. Louis, “the music coming in clear and loud on my radio, without a single trace of static.”

Gray made another attempt at an altitude record on November 4, 1927. On this attempt, his luck ran out. The barographs aboard the craft showed that he had reached an altitude of over 43,000 feet, but his lifeless body was found in the balloon basked in a tree near Sparta, Tennessee. He was posthumously awarded the Distinguished Flying Cross, and he is buried at Arlington National Cemetery.



Bernice Ozmuh, WIBO Chicago, 1927

1927SepRadioDigestShown here on the cover of the September 1927 issue of Radio Digest is Miss Bernice Ozmuh of WIBO, Chicago.  According to the magazine, she was the sweet contralto voice that was especially loved by the little folks who listened to her twilight lullabies.  She reported that her favorite role at the station was as gypsy story teller.

The station shared a frequency with two other Chicago stations, WCRW and WHT. In 1928, it carried the audio portion of an early television broadcast from WCFL.  It apparently went dark in 1933, as reported by the Chicago Tribune, May 23, 1933,  when the frequency was assigned to a station in Indiana.



Transistor Radio Repair, 1967

1967SepRadioElectronics1Fifty years ago this month, the September 1967 issue of Radio Electronics gave some pointers for servicemen to tackle the repair of small transistor radios. The article acknowledged that many radio men were unwilling to take on such a small job: “Don’t look at that small pocket transistor set and say, ‘We don’t fix them.’ Why let Joe’s Radio Repair down the street have the job?”

But there was money to be made, as long as the repairman could work efficiently. And more importantly, the customer probably owned other radios and televisions:

Why learn transistor radio servicing? One of our customers–Mr. Jones—has eight of them in his household. We repair them and make money doing it. Oh, yes . . . I almost forgot: Mr. Jones also has two automobiles with a radio in each, two TV sets, one small table radio, and I just sold him a big stereo set last Christmas.

1967SepRadioElectronicsThe key philosophy of repair was that “basic equipment with knowledge beats elaborate equipment and no knowledge.” After checking for obvious problems, the best starting point was at the volume control, where an AF signal was injected. Then, the serviceman would work his way back injecting AF, IF, or RF until the bad stage was found.

Stubborn little culprits were sometimes the source of trouble. For example, the author encountered one set that was going through batteries much faster than expected. The problem turned out to be a short across the power switch–the radio was never completely turned off. Instead, it was just turned down all the way to minimum volume.

Radios sometimes got dropped, resulting in a cracked printed circuit board.  Of course, the ideal method of repair would be to order a new board and move all of the parts.  But no customer would want to go to the time and expense of doing this.  And it was a relatively simple matter to locate the break and jumper the broken traces (and a few others, for good measure) with hookup wire.



Staff Sergeant Staff Sergeant Gerald W. Wagner, Japanese POW 1942-45

1942Aug8RadioGuideA few months after the fall of Corregidor,  this letter appeared in the August 8, 1942, issue of Radio Guide.

An earlier issue of the magazine had carried an item about Army nurses who had escaped from Bataan. This was spotted by one Mrs. G.C. Wild, originally of Rapid City, South Dakota, who was then in Richmond, Kentucky, on a defense project. Mrs. Wild was the sister of Staff Sergeant Gerald W. Wagner, who had been assigned to the Sternberg General Hospital in Manila. She and her mother had no word from Sgt. Wagner since February, 1942. After reading about the nurses, she wrote to the magazine asking if they could pass along her request for information about her brother, in the event that one of the nurses could provide some information as to his fate.

While the magazine had no way to contact the nurses, it published the letter, and asked any readers who knew any of the nurses to pass along the plea.

While it’s unlikely that the letter writer received any reply to her plea, it appears that Sgt. Wagner survived the war. He is listed as having been liberated from the Cabanatuan prison camp, and the report of the liberation appears in this February 2, 1945, newspaper report.  He was later awarded the Bronze Star.



American POW’s in China, 1942

1942Sep14LifeSeventy-five years ago today, the September 14, 1942, issue of Life magazine carried some of the first photographs of American prisoners of war, both military and civilian, held by Japan.  The photographs appeared in an English-language magazine published in Japanese-occupied China with the unlikely title of “Freedom,” which detailed the supposedly benevolent intentions of the Japanese toward the Asiatic people.

The photographs of the American prisoners were published to show the supposedly humane conditions the prisoners were experiencing.  Included were the photos shown below, which supposedly depicted the prisoners receiving radio receivers for entertainment during their confinement.

1942Sep14Life2This first photo shows the gift of the receivers to three representatives of the prisoners, standing at attention while they accept the alleged gift.  The recipient on the left is not identified.  Shown in the center is U.S. Marine Maj. James Patrick Sinnot Devereux, who later served in the U.S. House of Representatives from Maryland.  At right is civilian engineer Raymond R. Rutledge, who was working on a construction project at Wake Island when it fell to the Japanese.  The military-style hat he is wearing is actually an American Legion cap.  In another photo in the magazine, the cap is visible and reveals that he was a Californian.  The photo below shows Maj. Devereux (seated at right) with his unenthusiastic men allegedly listening to the radio in their barracks:

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Despite the upbeat text of the Japanese propaganda article, most of the photos depict obviously unhappy men such as those shown below, in which they are shown signing phonograph recordings which were later broadcast in POW broadcasts from station JOAK in Tokyo:

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Getting A Job In Two-Way Radio, 1967

1967SepEEFifty years ago this month, the September-October 1967 issue of Elementary Electronics told a young man just how to build the impressive resume shown here, in order to “make a mighty buck as a ticketed tech.” The article explained how possession of the “ticket,” a second class radiotelephone operator license, along with a bit of skill, could open the possibilities of a career as a two-way radio technician.

Jobs were available with service shops, manufacturers, police and fire, railroads, or other employers. Or, with a bit of experience, a young man could start his own shop and go into business for himself. Five million licensed transmitters were in operation, and all of them required service by a licensed technician.

For those with some electronics knowledge could study for the exam by themselves. Or those starting from scratch could enroll in a correspondence course.

To build experience, the article advised “get a novice ham license (very easy to do), buy a second-hand FM mobile radio unit or base station, and modify it for operation in the two-meter ham band. Also, but a ham rig kit–preferably an SSB transceiver, because SSB will be in wide use in the future. In short, get plenty of practice building, tuning and using two-way radio and thus get the most mileage from your ham ticket.”

The result of this preparation would be an impressive resume similar to the sample shown above. What employer wouldn’t jump at the chance to hire a general class ham, complete with membership in the ARRL.

With those preliminaries out of the way, it was time to get a job. Those who didn’w want to relocate could send resumes to shops in town, to the police and fire departments, and other large two-way radio users. Or for those who wanted to venture out to the possibility of relocating, the article provided addresses of where those resumes could be sent. It even suggested putting a “situation wanted” ad in a professional magazine.



1917 Spy Antennas Everywhere!

1917SepEEA hundred years ago this month, there might not have been a spy behind every tree. But there very well could have been German spies using those trees to conceal secret antennas, and the editors of Electrical Experimenter, in the September 1917 issue, were doing their public duty to warn Americans of the potential threat. Some possible secret spy antennas are shown here, along with the warning:

In preparing this article we have endeavored to show the unsuspecting
public how an enemy agent may either send or receive radio messages
by means of the most innocent appearing objects.

The Editors thought it best to give the article wide publicity, in order
that patriotic citizens may the better apprehend possible spies, who might be using secret aerials of the types illustrated.

The article is intended for public enlightenment, as well as for the
country’s safety.

According to the article, there could be a spy cleverly using your shade tree as an antenna, and it was a good idea to go out and check: “Have you examined your shade trees closely this summer? Don’t be surprised if you find a wire cleverly painted to match the bark on the tree and leading up to the various branches. It is readily possible for a persistent member of the enemy espionage squad to thus rig up a tree areial, and it is not necessary to travel very far to find a sufficiently large tree, which would serve as a framework for several hundred feet of insulated wire.”

A similar warning was warranted for those hanging their laundry out to dry: “If you live in the city (or even in the country) and have occasion to use a metal clothes-line of any appreciable size, it might pay you to closely scrutinize the supporting framework to see whether or not some alien enemy has been at work in an effort to use it for wireless communication purposes.”

These spy antennas could be anywhere, as shown in the illustration above.

Elsewhere in the same issue is the report of the U.S. Government blowing up the wireless tower at Shoreham, Long Island, erected at the cost of $200,000 by Nikola Tesla some twenty years earlier. The structure was no longer in use, but “during the past month several strangers had been seen lurking about the place.” Those lurking strangers could very well have been German spies, hanging around the 185 foot tower to use it as an antenna to contact Germany. Therefore, the Government blew it up.

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